1. Field of the Invention
The present invention relates to a thermal reactor apparatus used to treat industrial effluent fluids, for example effluent gases produced in semiconductor and liquid crystal display manufacturing processes. Specifically, the present invention relates to improved safety, reliability, monitoring and control features and components for said thermal reactor apparatus.
2. Description of the Related Art
The gaseous effluents from the manufacturing of semiconductor materials, devices, products and memory articles involve a wide variety of chemical compounds used and produced in the process facility. These compounds include inorganic and organic compounds, oxidizers, breakdown products of photo-resist and other reagents, and a wide variety of other gases and suspended particulates that must be removed from the effluent streams before being vented from the process facility into the atmosphere.
Semiconductor manufacturing processes utilize a variety of chemicals, many of which have extremely low human tolerance levels. Such materials include, but are not limited to: gaseous hydrides of antimony, arsenic, boron, germanium, nitrogen, phosphorous, silicon, and selenium; silane; silane mixtures; hydrogen; organosilanes; halosilanes; halogens; acid gases; organometallics; oxidizers such as O3, NF3 and ClF3; and other organic compounds such as alcohols.
A significant problem of the semiconductor industry has been the consistent and effective removal of these materials from the effluent streams. While virtually all U.S. semiconductor manufacturing facilities utilize scrubbers or similar means for treatment of their effluent streams, the technology employed in these facilities is subject to failure and inefficiencies and as such, not all toxic or otherwise unacceptable impurities are removed.
Point-of-use abatement systems add a level of redundancy, reliability, and capability by removing pollutants from an effluent stream before the effluent is diluted in a house scrubber system. Combining and diluting effluent streams in the house system is disadvantageous for several reasons including, but not limited to, decreasing abatement efficiency due to the large, diluted volumes that must be treated, and increasing risk of unwanted side reactions, particle formation, and corrosion in a house scrubber duct system. Further, failures of the house scrubbing technology present substantial safety hazards to the personnel, facility, and the environment. The, point-of-use abatement systems combined with the house scrubbing system adds a level of redundancy and reliability consistent with critical safety standards practices of the semiconductor manufacturing industry.
Thermal reactors are increasingly being used to process effluent waste streams to decompose the toxic materials, converting them to less toxic forms. For example, the improved thermal reaction unit disclosed in co-pending U.S. patent application Ser. No. 10/987,921, filed Nov. 12, 2004 in the name of Ho-Man Rodney Chiu et al., and entitled “Reactor Design to Reduce Particle Deposition During Process Abatement,”abates at least 95%, preferably at least 99%, of waste effluent components including, but not limited to, CF4, C2F6, SF6, C3F8, C4F8, C4F8O, SiF4, BF3, BH3, B2H6, B5H9, NH3, PH3, SiH4, SeH2, F2, Cl2, HCl, HF, HBr, WF6, H2, Al(CH3)3, alcohols, oxidizers such as O3, NF3 and ClF3, primary and secondary amines, acid gases, organosilanes, organometallics, and halosilanes. Importantly, the decomposition removal efficiency (DRE) of the improved thermal reaction unit is greater than 99% and it is designed to reduce the deposition of unwanted reaction products, such as silicon oxides, within the thermal reaction unit.
As the art of thermal abatement develops, so has the necessity for developing safety, reliability, monitoring and control features for said thermal reactors. Safety features are especially important because the abatement of effluent waste streams in thermal reactors is facilitated by the introduction of fuels, e.g., methane, natural gas and/or hydrogen, to the thermal reactors for combustion and oxidation therein. The high temperature generated by the combustion of said fuels assists in decomposing the toxic materials of the effluent stream therein. Clearly, monitoring and control components are necessary to minimize the risk of ignition and deflagration within the reactor or reactor housing due to fuel leaks, as well as making sure the reactor efficiently abates the effluent waste stream.
Accordingly, it would be advantageous to provide improved safety, monitoring and control features for thermal reactors to ensure personnel safety and improve the efficiency of the abatement process.